A YAC contig across the fragile X site defines the region of fragility.
Hirst MC., Rack K., Nakahori Y., Roche A., Bell MV., Flynn G., Christadoulou Z., MacKinnon RN., Francis M., Littler AJ.
The fragile X syndrome is a common cause of mental retardation and is associated with a fragile site at Xq27.3 (FRAXA). Recently, evidence has been presented for the role of methylation and genomic imprinting in the expression of the disease. We have identified a site of methylation in patients by long range restriction mapping of the region. In this paper we present a YAC contig of this area, localise the CpG sequences which are methylated, and show by in situ hybridisation that the site of fragility lies within this region.